> I'd like my app to show the Open dialog at launch time instead of
> opening new document window.
> Would you tell me how?

Register for an NSApplicationDidFinishLaunching notification and
send the same message as the "open" menu command is connected to to
the first responder at that time. You may also have to implement that
shouldOpenUntitledWindow: method (not 100% sure on the name) in your
delegate to suppress the creation of a new document at that time.